Automatic party-line telephone system.



F. LUBBERGER AUTMMIC PARTY UNE TELEPHONE SYSTEM.

APPUCATiON LEUIUNEI6.19\0.

Patentet Oct. 9, 1917 5 SHEETS--SHEET l.

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APPLECAHEJN FME IJNE I6, 1910.

Patented (hat. 9, 1917.

5 SHLETS-SHEET 2 F. LUBBERGER.

AUoMANc PARTY LINE TELEPHONE SYSTEM.

Patented Oct. 9, 1917.

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APPLICATION flLED JUNE l5, |910.

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UNITED STATES PATENT OFFICE.

FRITZ LUBBEBGEB, F UHICGO, ILLINOIS, ASSIGNOBO AUTOMATIC ELECTBIO COMPANYOF CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

AUTOLIATIG PARTY-LINE TELEPHONE SYSTEM.

Bpeeicetlon of Letten? :Patent Patented Oct. 9, 1917.

Application filed June I6, 1910. VBerici No. 567,299.

,To alt whom it may concern.'

Be itknown that I, Fnrrz LUBnRoEn, a

i. subject of the Emperor of Gern'ian Y, and

resident of Chicago, Cook countyfI linois, have invented a. certain new and useullmprovement in Automatic Party-Line Tclephone S stems, of which the following is a specification.

My invention relates to telephone exchange systems in which party-lines are employed. It relates more particularly to` automatic exchanges of that type ordinarily known as three-wire systems, to-wit, systems in which e ground is employed at the substations for controlling the automatic switches at the central station. More especially, however it relates to a three-Wire system of this kind in which the party-lines are operated on the twowire principle-that is to say, by controlling the automatic switches over the two sides of the calling line in series. This, it has been found, is an advantage, as interference between subscribers on the 'same line is more easily prevented and guarded against in a two-wire system than 1n a three-wire system. Thus a three-wire automatic system in which the party-lines are operated on the two-Wire principle is less com licated and more efficient than a system in w` ich the party-lines are also operated on the threewire principle.

The `object of my invention `is to provide an improved arrangement whereby a partys line subscriber in a system of the foregoing cl'narecterV may si nel another subscriber on the samelino without firstv operating the calling mechanism at the substation of the calling' subscriber, und by simpl operating a 'push button after'the removaoA therece1 ver at the calling substatiomthus enablingthe arty-lne subscribers in a system Aofhthis kind to intercommunicate in e very simple `and satisfactory manner, as will hereinafter more fully appear. i

To 'thisand other useful en st .my invention conists in. matters hereina-l Yr set foi-th andclaimedg. L v

Inthaccompanyjng drewmgeEi ree 1,

(Fig."1).`and al@ ed'strai'ght lnesub'sta.

ti@ A? ille Systemembodyingthefrinei: .I

returned to normal position the jep substations A and A to the line conductors of which there is allotted at the central oilice an individual or line switch C. At D there is shown a master switch for controlling a jgroup of line switches, such as the one shown at C. The line switches of this grou have common access to a number of trun lines which leed to so-called selector-repeaters E (Fig. 2). A number of'these selectorn repeaters have access to a number of second se ectors F (Fig. 3), which latter selectors in turn have access to a number o third selector switches H. These third selectors HA in turn have access to a number ofconnector switches I ('Fig. 4) by means of which con 70 nection may be completed to eubscibers lines.

Fig. 5 is a dia ammatie view of a portion -of the central o ce ap aratus, showing the essential features of t e master .switch D T5 (Fig. 1).

The automatic substations with which-I have chosen to illustrate m invention are of' two types. The substations A and A.

are of that type in which the central oiio'e 8i) apparatus is controlled over the two sidesl of, the iine in series. The substation A is of the character in which the substation appairatus is controlled by ound impulses over the two sides of the lne substation A comprises the usual receiver-2,'

switch hook 3, transmitter 4, induction coil f 5, ringer 6 and condenser 7. Since it is at automatic substation it is also provided with; f' the impulse springs 5 and 9 and en impulsc'u are so arran d `that as they are rotvfted fog,-

Wardto cal digit-the Slrin Y' la" artnet neectgybut S i impi rings and 9 are scparated'hy the teeth l; a mim er* I* fLIfn the substation A (Fig. 4.) the'im vniet 108 lwhen 1c in provided with um wenn y 'ticalimpulse teethlT and one rotarygfinr ulse tooth 18., These teethv'are so arranged gilet as the impulse wheel is rotated forward through the medium of the dial the rotary K separately. Tljgel'` an r holes, liga a pushH 96 tohth 18 forces the so-called rotary impulse spring 19 into engagement with the ground spring 21. As the wheel 16 returns to normal position the vertical impulse spring 2O is forced into engagement with the ground spring 2l a number of times corresponding to the digit called, after which the rotary spring 19 is once more forced into contact with the spring 21 by the tooth 18. While the impulses are being transmitted the connection between the two sides of the line is broken between the sprin s 22 and 23, which come into engagement w en the receiver is removed from the switch hook, but are permitted to disengage vby the dog 24 whenever the dial is out of normal posltion. As the switch ook descends the arm 25 momentarily presses the springs 26, 27 and 28 into engagement.

The line switch C (Fig. 1), which is in dividual to the line of substations A and A', and the master switch D are modified forms of the general types of line and master switches disclosed in British PatentfNo. 26.301 of 1906, and in the American [clephone lm/.rural of New York, N. Y., of J une 6, 1908. As herein represented, the line switch C comprises, among other details, a plunger 38 (Fig. 5) attached to the end of a so-called plunger arm 39 which is controlled by the magnet 40. The magnet 40 also controls the rela armatures 41 and 42, and is composed of our windings, namely, a pull-in winding 43, a holding or cut-off winding 44, line winding 46 and an auxiliary windin 45. The core of the magnet is provided near the center of its len h with a lateral projection 47 by means of w ich the magnet is mounte upon the bracket 48, upon which latter t e armatures 39, 41 and 42 are pivoted. With thismethod of mounting the magnet the magnetic circuit of the windings 43 and 44 is maintained separate from that of the windings 45 and 46, so that the armatures on one'end of the magnet are not affected by the ener ation of the windings upon the other en 0f the two windings upon the upper end of the magnet'only the winding 43 is Strong enough to attract the plunger arm 39 from its normal position. The winding 44 is not strong enough to thus operate the plunger arm, but will hold it in an operated position after it has been drawn down hy the winding 43. When the plungerY arm 39 is attracted by the magnet 40 the plunger of the switch is forced into a banl of contact springs, forcing springs 49, 51,

53 'and 55 irito engagement with springs 5 0, y

52, 54 and 56, respectively. A1though only one set of springs 49-56 is shown, each line switch C is provided with a' number ensuch groups of springs, each group formin the terminal, of a trunk line leading to a se ector 1'). Each trunk line is multi led through i thc corresponding springs o all the line einem rotating the ratchet w4 l 59, lhe -rate et wheel 59 is connected h@ shaft 50 by means of a link 61 .in ir A aime# *ibut il rotary motion of the ra tj' l is tran= mitted to the plunger sha t 57, partiti to it an oscillato motion about toghe t 60, so as to move t e idle plungers back andati forth in front 0f their trunk terminals. To the shaft there is `secured a locking plete 62 provided near its outer edge with a number of openings 63 which are adapted to be engaged by the pin 64 upon the cn'd of the armature 65 of the relay 6d.- Tlil- Opelllng in the plate B2 are so spaced that lll pill .54 can engage one of them only when Eh@ )lilik gers that are in locking engagement wit the plunger shaft are directly in front of the corresponding trunk terminal. The u1u-itin switch is also provided with a bank of coll-1 tacts comprising a common segment 35 and one individual segmento for each trunk to which the line switches have access. The wiper 29 always keeps the common segment in electrical connection with the individual segment corresponding to the trunk line he fore which the idle plungers are being held by the master switch.

Associated with each trunk line which leads from the line switches C to the selectors E there is a relay 67. Common to a number of these trunk lines there is a ringe ing interrupter mechanism comprising a motor magnet 68 and a ratchet wheel 69 which is secured to a shaft 70 to which are secured the two inten-u .iter wheels 71 and 72. These wheels 69, 71 .and 72 are shown separa-ted for convenience 0f UUSIMJOIL The circuit of the motor magnet is 6011-.

trolled by the double-wound relay 73 The wheels 71 and 72 control the two pairs of springs 74 land, 75, resctively. These springs are so controlled t at .es the wheels,

revolve the two pairs will be urmitted' to engage alternately -unrl in suc a manner that one pair is. disengagedbefore the next pair is permitted to come into engagement. The pairs of springs 74 and 75. control the circuits of therelays 76 arid 77,. respectively,

which in turn controlthe connections of the ringing current generators R and R These generators generate ringing current of dif:

ferent frequencies. "-,The ringers at each of.

the substatons A and A' are adapted to respondto current furnished by only one of these generators. For instance, the ringer 6 at substation A may be made to respond 'only to current furnished by generatonR,

while the ringer 76 at substation A will only be a'ected by current from generator R.

The selector-repeater E is of the general type of selector switch disclosed in United States Letters Patent #815,321, granted March 13, 1906, to Keith, Erickson t Erick-- son, being modified, however, to operate by impulses which are delivered from a calling substation over the two sides of the line in series. Besides performing the function o1 a selector, the selector E is provided with means whereby, after it operates to place its wipers in connection with an idle trunk line, said selector may then receive impulses from a calling substation over the two sides of the line in' series, and repeat impulses over the two sides of the trunk separately to operate switches of the socalled three-wire type. Among other details the selector-repeater E comprises a set of wipers 79, 80 and 81 carried upon a shaft (not shown) which has a vertical and rotary motion controlled by the vertical magnet 82 and rotary magnet 83. rl he usual side switch comprising the wip:` s 85 and 86 is controlled by the private nag'net 87 in the usual manner. The operation of the switch is controlled by the calling subscriber through the medium of the relays 88 and 80. Means for restoring the switch to normal position is provided in the release magnet 90. The selector-repeater E is released immediately upon the energization of the reY lease magnet, rather than by its denergization, as shown in said selector patent. An arm 91 is attached to the switch shaft and holds spring 92 in engagement with spring 93. and 'spring 95 out of engagement with spring 94, as long as the switch shaft is in its lowest or normal position. The talking circuit through the selector includes the two condensers 96 and 97. The armature of the .rotary magnet 83 has no finger for controllimiv the armature of the private magnet .87, as shown in said selector patent, but the private magnet is controlledv by the rotary magnet electrically through the medium of the grounded contact point 99. The selectors F and H are also of the type disclosed in the said selector Patent No. 815,321, but are not modified to operate over the two sides of theline in series, or to repeat im-` pulses.

`The connector I (Fig. 3j) is of the general type of connector switch disclosed in United States Letters Patent #815,176, granted March 13, 1906, to Keith, Erickson t Ericki son, its circuits being modified somewhatin order vto adapt it for operation in a common battery system. i The line switch C is of the type disclosed in rthe British Patent #26,301 ofl 1906, and the American Telephone Journal referred to above.. The line switch C has access to trunk lines which lead to thmwire/selectors similar to the selectors F and H, Fig. 3.

At R2 there 'is shown a ringing current generator, and at L a busy signaling apparatus consisting of a current interrupter 100 and induction coil 101 is shown. At B there is shown a battery which furnishes current for operating the central office switches and for talking purposes,

. Having given a general description of the apparatus illustrated herein, I will. now describe in detail the various operations by means of which one subscriber may signal and obtain connection with another. It will first be explained how a subscriber at the party line substation A may call substation A2 (Fig. 4), the number of which is assumed to be 22220. The removal of the receiver at the substation A preparatory to making a call allows the spring 103 to disengage spring 102 and engage spring 104, whereby the circuit of the ringer 6 is opened, and a circuit is closed through the line Winding 46 of' the line switch. C. This circuit eX-v tcnds from ground G through springs 105 and 10G, line 107, push button springs 108, springs 103 and 104, springs 9 and 8, primary vvinding of induction coil 5, transmitter 4, line 109, springs 110 and 111 and winding 46 to battery lead 112. The energi nation of the windin 40 serves to attract the armature 42, whic operates to force the spring 113 into engagement with spring 105, whereby a circuit is closed through the pullin winding 43. This circuit extends from ground G' through springs 105 and 113, windings 43 and 45, Contact point 114 and rmature 65 to battery lead 112. -The winding 43, upon energizing, attracts the armature 41 and plunger arm 39. The armature 41, upon being attracted, operates to disconnect the line winding 46 and ground G from the callingr line. The armature 42 does not fall back immediately upon the deenergization of the winding 46, but remains held up b current flowing in the-.Winding 45 until tie plunger arm 39 forces spring 115 into contact with sprin to denergize slowly to'hold the arm ture 42 in its operated position for an` in` eht lon er.V Before the armature 42 is restored su ciently to break the circuit of windlng 43 a circuit is closed through the winding 44 yin the following manner A springs- 49fand 55,.l are forced into contactY with springs 50 and 53, respectively, by the plunger of the line switch a circuit 1s closed through the. line relays 8S and` 89 of the selector-re eater E. This circuitextenpls from ground x2 through relay 89, trunk con-l ductor 117, springs 241 and 240, s rings 56 and 55, thence over the 4heavy con uctors to and through substation A and backaover the other side of theline and through relay,

116; fwvhereby. the winding 45 is short-circuited and c used When theV es to arbitrary ,lead 112. The relay se,

K `the pin 64.

upon energizing, operates to close a clrcuit through the` relay 123, said circuit extending from ground Ga through springs 124 and 125 andrelayf'lZSto'batterylead 112. The relay "123, upon energizing, operates to close the circuit of the holding winding 44 of the line switch C, said circuit extending from ground (i through sprin s 126 and 127, conductor 119, springs 52 an 51 and winding 44 to the battery lead. The current in this Winding serves to hold the plunger arm 39 and armature 41' in their operated positions after the windin 43 has been denergized. The energization of the relay 123 at the selector E also extends a guarding potential from grounddi'4 over conductor 128 to the connector private bank contacts of the calling line.

When the springs 53 and 54 are forced into contact by the plunger of the line switch a circuit is closed through ther master switch r'elny 129. This circuit extends from ground (is through springs 53 and 54, contact point 130, wiper 29` segment 35 and relay 129 to battery lead 112. The relay 129, upon 'energizing operates to close a circuit through the relay 66. The relay 66, upon energizing, operates to withdraw the pin 64 from the plate 62 and to close the circuit of the motor ma et 58. Thiscircuit extends from ground 6 through magnet 58, interrupter springs .131, contact point 132 and armature to battery lead 112. As long as the armature 65 engages contact point 132 the magnet 58 operates in a man ner similar to that of a buzzer to rotate the ratchet wheel 59 ste the idle line switch p ungers away from the trunk just seized. After the plungers have been advanced a short distance the wiper 29 leaves the coni-.ict point 130 and allows the relays 129 and 66 to denergize. The armature 65 does not fallback immediately upon the lciinergizaton of relay 66, but remains in contact with contact point 132 until the next opening in the late 62 passes under When t e next opening does pass under the pin 64 the amature 65 falls back, forcing the p'n intothis opening to lock the plunger s ft, and breaking the circuit of the motor magnet V58. The foregoing isl the operation of the master switch incase the next trunk. line after the one seized by the switch C is idle. If, however, this next trunk is busy the wiper 291iinds the corresponding contact in the master switch bank grounded, and consequently the relays 129 and 66 remain energized while the next opening is passng'under the pin 64 and the plungers are ,carried 'past the busy trunk to an idle one. Ags; lpng as the muster switch is operating tlie armature 65 is disengaged from the spring 114, und spring 114 engages by step to advance take place immediately upon the removal of the receiver at the calling substation.. The calling subscriber now voperates his dial for the first digit 2 of the desired number. As the wheel 10 returns to normal position after being rotated for this digit, the impulse springs 8 and 9 are separated twice momentarily. Each time these springs are separated the energizing circuit of the relays 88 and 89 of the selector E is broken. The denergizetion of relay 89 in response to these impulses is Without function. Since the relay 123 is slow acting it does not have time to denergize during the momentary interruption of its circuit by the denergization of relay 88. 'Thus cach time relay 88 dener- Isizes -a circuit is closed from ground Gr3 through springs 124 and 134, springs 135 and 136, slow acting private magnet. relay 137, vertical magnet 82 and side switch `wiper 86 to battery lead 112. Since the digit called is 2 the vertical magnet receives two impulses over this circuit and operates to raiSethe switch shaft two steps. The relay 137,- being slow acting, is energized by thc first impulse through it in series with the vertical magnet and remains in its operated osition until the last impulse is delivered.

n its energized position the relay 137 operates to close a circuit4 from ground Gr7 through springs 138 and 139 and private magnet B7 to battery lead 112. The relay. 137 .denergizes shortly after the last impulse is delivered-to the vertical magnet and breaks the :circuit of the private magnet 87, which in turn denerg'lizes to permit the side switch to pass from rst to second position. The. movementof side switch wiper 36 from first to second position disconnects the battery from the vertical magnet and closes a circuit through the rotary ma net 33. This circuit extends from ground s through mterrupter springs 140, rotary magnet 83 and 'side switch wiper 86 to battery lead 112.

armature 141 and private magnet 87 to battory load 112. It' the iirst trunk upon which the wipers o t the selector are rotated is idle, the primis muguet defina-lires :is soon as the urnutture of the rotary muguet falls back. This energgzzuion una( eloucrgizutiou of the private muguet permits the side switch to pass to third positioii. thereby brushing the circuit oi' the rotary muguet 83 out leaving the wipers resting upon the contacts of the first trunk line. lf, however, the iii-st trunk upon which the selector wipers are rotated is busy, the private 'wiper 81 finds thc contact which it engages provided with :i guarding ground. Thus e. locking` circuit conipleieii from ssiil guerriing ground through simii. wiper 81, sirio switch wiper Sli :anal private muguet fi? to biittcry lou-ri 11;?. The privato 1n: Yuri reins-eins cnorgghierl enti locks the 1.. in second position siter the roury muguet Llciioergfif/svs the first time. The rotary insg? net dif then continues to advance the wipers step by stop until the private Wiper 81 enA gages e nongrounrlcd contact of :1u idle trunk. whereupon the primate magnet Ileenergizes und nernnts the side switch to piss to third position. as iescrilu-:i ohci' Besides hreehing the circuit ff' the private Inco/Tnet the gris-sage of the switch info-A videsr guarding' poter-tial for the seu lector priva-ite. honk contents ot the seized trunit This wording potential extends from ground G9 through side switch wiper 85 and shaft wiper 81 to said private ostili conm tents.

The relays 88 und 89 of the seieotourepeuter E operate in response to Ythe impulses for the seeonr digit 2 in the suine manner as for the tiret digit. Sincei how ver, the side switch ot the switch E is in third position the denergisation of the rehty S8 serves to close a circuit through the relay 142 insteed oi' the vertical magnet titi. ri'his circuit extends from ground Gr3 through the springs 124 und 134, springs 135 und 136. relay 137, rele'y 1li-r2 und Sitte switch Wiper SS t0 the buttery lend 112. The relay fl is slow acting und consequently is energized by the first impulso through it, :out remains in its ei'iergized position ifi :iii the ini-- pulses ior the light ire wl, In its energized po tion the :y 15x35 esti-,uds u connection from the sprint` 1.13 of the rel-uy 88 through the springs ly-"l :unl 1413 und shaft wiper 7i) to the wrticul trunk conductor 152, und also cineos u circuit through the reluys 116 und 11T. This circuit ex tends from ormoni il through the springs 126 unil 127 oft the reizt); 122i, springs 148 und 1 re we liti :oni |47 und side switch Wiper -Sfj to the listrry nani 112. The com giusti-.in ot' il, is without @tire-:t eect :it this .nie the troni?. con ductor iii?, is .i the. sprl, lf3

of the relay 88 during the time the relay 88 is operating in response to the impulses for the second digit, 1t follows that each time the relay S8 energizes, si ground impulse is transmitted from ground Gs through the springs 151 und 14:3, springs 144 und 145 to the vertical trunk conductor 152. Since ythe digit called is 2 the relay 8S is deuergized and energized twice, thereby transmitting two such ground impulses to the conductor 152. The lust impulse continues until the relay 142 denergizes after its circuit is broken by the return of the relay 88 to its energized position after it has dencrgized for the lust time. Then the relay 1412 de cuergizes it ulso iirenlrs the ci rcuitsof relays 146 :roti 147. The relay 146, being quick rioting., donergises immediately und cornpletes u. connection from ground Gw through springs. 155 and 156, springs 157 und 15S and shaft wiper S0 to the rotary trunk conductor 153. The slow acting rel uy 1117 denergizes :ritter e moment und disconnects this 1ground from the rotary trunk. 1t is thus evident that Wien the substation. calling device is operated. for the second digit 2 the selectorrepeatcr E operates to transmit two ground impulses. to the vertical trunk conductor 152 und mu. impulso to the rotary trunk oon {uctor 153. During the time these impulses are boing repeutefil the. circuit of the private magnet is maintained by the relay 1,157. The side switch has passed out of control of the privato magnet, so that its energizution at this time simply serves to open up the connection between Athe culling line und the trunk line While the impulses are being repeated.

The two impulses which are repented to the trunk conductor 152 through the side switch wiper 159 und vertical line rcluy 160 of the selector F Fig. 3) to buttery lead 112. T his relay, upon ener rising.y completes s. circuit from ground ix through springs 161 und 162, springs 163 und 164 und vertical magnet 165 to battery lead 11". The vertical magnet operates i'i response to the two impulses over this oirouit to raise. the shaft und wipers two steps. The impulse transmitted to the rotary side of the trunk hy the switch E then posses through side switch Wi )or 160 :unl rotary linel relay 167 of tho selector l` to the huttery loud. The roluy 161- then ol'im'ntes to semi one impulse from ground li through springs 161 aiui 168 and private magnet 169 to the buttery lend. The private nmgnet, upon energizing und denergizn permits the side ,switch to pass to seeom position, whereby a circuit is closed through the rotury umgnet. This circuit extends from grounf G1? through side switch Wiper 170, interruptor springs 171 und rotary magnet to izittcry icuii 112. As in the selector tho rotary magnet operates to rotate the wipers step by step as long as the side switch remains in second position. When the rotary armature is attracted it 'presses down the'armature of the private magnet 169. If the rst trunk is idle the private magnetarmature falls hack the first time the rotary magnet denergizes and allows the side switch to pass to third position. If, however, the first trunk is busy the private Wiper 173 finds a ground potential and closes an energizing circuit through the private magnet, which causes the side switch to be locked in second position. This circuit extends from said grounded private bank contact through wiper 173, relay 174 side switch wiper 175 and private magnet 169. The relay 174 does not receive suliicient current over this circuit to be operatively energized. After an idle trunk is found the side switch passes to third position just as in fthe selector E, whereb the line connection is extended through side switch wipers 159 and 166 and shaft wipers 176 and 177 to the selector H. The trunk line is rotected against seizure by any other seector by a ground potential extending from ground G through side switch wiper 175, relay 174 and private wiper 173 lto the private bank contact 178, and thence to the corresponding contact in the banks of all selectors F that have access to the selector H.

When the substationcallin device is operated for the third digit 2v t e selector repeater E operates in the same manner as for the previous digit to transmit two iinpulses to the vertical trunk conductor 152, followed by one impulse over the rotary conductor 153. These impulses, however,Y

ass through the line relays of the selector causing it to operate in the same manner as explained for the selector F to extend the connection to a connector I over trunk conductors 179 and 180.

The impulses which are repeated to thevertical side of the line for the `fourth digit 2 pass through the selectors tical line rela 182 and upper winding of relay 183 to battery lead 112. The energization of relay 183 at this time is functionless. The energization of relay 182l serves to close a circuit from ground G through springs 184 and 185, springs 180 and 187, side switch wiper 188 and vertical magnet 189 to the battery lead 112. Since the digit called is 2 the vertical inagnet operates twice to raise its wipers op osite the second level of bank contacts. he rotary impulse for this digit passes through the rotary line relay 190, lower winding of the relay 183 and springs 191 and 192 to the battery lead 112. The relay 190, upon energizing, closes an energizing circuit 'from ground G through the springs 184 and 193, private magnet 194 and springs 191 and 192 to the battery. The private magnet F and H, verl 194, upon energizing and denergizing, permitsthe side switch to pass from first to second position, whereby the rotary magnet 195 is brought under the control of the vertical relay 182.

Since the last digit is 0 ten impulses are transmitted over the vertical side of the line and through the relay 182 when the substation calling device is operated for this digit. The intermittent energization of the relay 182 for this digit causes a series of impulses to pass from ground G through the springs 184 and 185, springs 186 and 187, rotary magnet 195 and side switch wiper 188 to battery. The rotarymagnet operates in response to these impulses to rotate the wipers onto the contacts of the desired line. The impulse over the rotary side of the line which follows this last set of impulses over the vertical side energizes the rotary relay 190 once more, which causes the private magnet to trip the side switch to third position if the called line is idle. The movement of the side switch wipers 196 and 197 to third position completes connection with the called line through the shaft wipers 198 and 199, while the wiper 200 supplies a guarding ground potential through the shaft wiper 201 to the connector private bank con- Jfacts of the called line. The wiper 200, in third position, also completes a circuit from ground G15 through wipers 200 and 201 and cut-ofi' relay 202 of the line switch C to battery. The relay 202, upon energizing, operates to disconnect the switch C from the lcalled line and connect the rotary line 203 with the bank contact which is the Wiper 199.

After the calling device has been operated for the last digit the push button 14 at the calling substation is pressed in order to cause the called substation to he signaled. The pressing of button 14 removes the shortcircuit from around the resistance 15, inserting it in the circuit of the line relays of the selector E. The line relays 88 and 89 of the selector E are so adjusted that when the resstance 15 enters their circuit the relay 88 remains energized, while the rela 89 permits its armature to fall back. he relay 89, upon denergizing, closes a circuit. from ground Gs through springs 151 and 143 of relay 88, springs 204 and 205, springs 206 and 207, springs 208 and 209, and thence to the trunk cnductor 152, and through switches F and H and the relays 182 and 183 of the connector I to battery. Since the side switch of the connector is in third position the energization of relays 182 and 183 completes a circuit through the ringer relay. This circuit extends from ground G14 through springs 184 and 185, springs 186 and 187, side switch wiper 188, relay 210 and springs 211 and 212 to battery lead 112. The relay 210, upon energizing, opens the engaged by @essere connection between the calling and called lines at a point between Springs .513 end 214, and bridges Foe ringer generator R across the called line to ring the laells 215. W'hen the button at substation A is released the relay 21H deinergiree. When the called subscriber removes hie` reaeiver in :weaver to the @all the Hiring LH and 3 are permitted to engage end the (failed substation gire- Vided with talking battu-y euri-eet over e circuit extending from grounf'l (-il at the Connector l through eide .ewiteli wiper Llull, lower winding oit relay 1115, riwrr relay springe 214 and 213, wipers 197 and 199, springs .617 and 315. line L03, primary ot' the induction coil and transmitter at. sul)` station A, springs 22 and 23, line :219, wipers 12M and 196, upper winding of relay 216 and .wpriugfs :liti :md 22() to battery leed 1.12. The romplete talking tiri-iut@ between the two lim-ff iS ,schwul liv Safety nomine tors.

After the .aiuierranion is eouxpleted the release ol the neutral other apparaius, is initiatrll l. \y the hanging up oi the revolver at thv calling' failaztatmu. The hanging up oli the receiver at station lu'ealte the ener giziug rirruit of the relaye *le mui 59 of the repeater l. The relay de. open denergizing, opt-rales to loe the ciruuits of relays liT and 11; in thv mule marmer :te when the relay w i|vi\ue1;1im ;,1.in :reponer to operating inn-aller". The .relay 1li.y upon ener2H gluing, losflnrireinl's of relaye 1.441 and 11T ae lu'wiouely traced., The relay Htl, upon lL-Elue fixing, also hrmalte the ifirezuit of relay 123, n'hirh eleiinergimvs :z time. The re-lny 12in, upon deinergfixiug,

. breaks the circuit of relay` Mil` 117, 137

` connector.

and 11%. 'l'lie relay 116 i5 quick acting und falls bark iuunediately, while the other relays are Slow acting and remain energized. for au instant. At the instant relay .146 le-- energizrs both trunk conductors 15;.)` and 1,52 are grouinled. Thil freund for the Condat'H tor 153 is supplied ltoiu ground (l u through springs 155, 1.50, '15T and 1525. 'lile ground for roniluutor 1.515 extends from ground (i3 at theI relay through :springs 124, and 131, springs 221 and 2015, springe 20.6 and 207 and springs 208 and 2119 to conductor The simultaneous grounding of". the two Sides ol' the trunk 15E-152% causes. relay 1.83 and both line relays 182 and 1li() of the ron nrrlor l to lio energized.

'lhe mwrgizailou o'l" relays 19,5%, 182 and ISNl vmnplrler.: ay vin-uit from ground fi" at seh-Pto:- ll through sido swileh wiper ""2 reenergized orer thi; ein' l he L'a'uif upon energizing, iniuua'liatelt rile The relay 223, upon energia a short.

completes a circuit from ground G at Selector F through side switch Wiper 175, relay 1171-, private Wiper 173, springs 229 and IU a yu! magnet 231 to Battery lead. 1152. The relay 174 and magnet :231 are both energized. 'llw relay 171, upon energizing, completes the circuit of the release magnet 2232. The manuele S1 and thus attract their armeturea and hold them in readiness to release the svlwtors il and l" when they drnergize. s eeen as the slow eating relay 147 of the seleotor E rleeergizes tha line relays o1 the connector I deuergize, and all circuits whieh were closed as a coneequence of their enurfi'ltation are broken. The release magnete of the Selectors Il and l" thereupon drnere'ae and release their respective switches. lNheu the relay 147 of the selector lt fleinergizes it elec closes the circuit of' thv rrlmeeiniignet liti, seid circuit extend- 'roni gro'unl (im through Springe 3.55; and e .i1-ings :E31 and :52115, Sprii'igs U4 and DI and magnet UU to battery. The magnet fill, upon rnrrgizing, allows the mechanism So return to normal. poeition. Then the ehn't reaches normal position the circuit of the re magnet is broken by the separation of priugs 94 and 95.

The line` Switch C is restored to normal Ellie foregoing le an explanation of how mnueriion is compil-tml with an 'idle line 1l rhiliue .#22220 had been buey when r-allml lrom substation A the wiper 20.1 o the .'ounvetor l would here found the oontzwt 31? grounded. This being the case, when the rotary relay 190 was energized tor the laat tune, instead of the side switch being lripped to third position, the c0nnector would here released. The energizine'cireuit for the release magnet in this am would have been the grounded pri- Mh bank contact 349 tl'irough Wiper 201, enitvh wiper 200 (the Side Switch heing in ond position), through springs and l oi the private magnet (which is energized oy the energizetion of relay' 1510), release magnet 227 and springs 211 and to battery. The magnet Q27, upon energizing, would here caused the conmwtor mechanism to be restored to normal lmeition. Now, when the calling subsrrilmr pressed the ringing bottom, the coneequeur euergizatiou ofthe vertal relay .189 olVI the connector would have energized the vertical magra-t 139 in a manner already explained. Ae soon as the shaft was raised from. its normal position the erm 252 would here permitted the springe 253 d .254 to ena-effe, 'iwrvlly completing a holy Signaling rrlf from lettery lead 112 through the winding uf induction coil 101, a1-.ld 251, :side switeh wiper 197 erde (in first position), springs 213 and 214, and thence over the heavy conductors to and through the substation A, back over the other side of the line and through the relays 182 and 183 of the connector I to the starting point. Upon hearing the busy signal the calling subscriber hangs up his receiver, causing the switches to be released in practically the same manner as has been described.

The foregoing is an explanation of how a subscriber on one line may obtain connection with another. If one part -line subescriber desires to call the other su scriber on his own line, however, he does not have to operate his calling device for the digits, but` simply removes his receiver and presses the button 14. When the receiver is removed the line switch C operates in ie same manner as has been explained to extend connection to a selector-repeater E. Now, when the button 14 is pressed the relay 89 of the switch E falls back, while the relay 88 remains energized in the same manner as when the button was pressed to signal substation A2. Since the shaft' of the switch E has not been raised from its normal position to permit rings 92 and 93 to separate, the falling bacs-,11; of relay 89 com letes a circuit from ground Grs at'relay 88 t rough-springs 151 and 143, springs 204 and 205, springs 206 and 207, springs 208 and 209, springs 92 and 93, conductor 120, relay 67 a'nd lower winding of relay 7 3 to battery lead 112. The lower winding of relay 73 1s of comparatively high resistance and prevents the relay 67 from being operatively energized over this circuit. The relay 73, however, attracts its armature and closes a circuit fro ground G13 through interrupter 236, springs 238 and 237 and motor magnet 68 to battery lead 112. lhe magnet 68 then begins to rotate the wheels 71 and 72. After the wheel 71 has moved a short distance the sprin s 74 engage, whereby a circuit is close from ground G through relay 76. The closure of springs 258 and 239 'of the relay 7 6 shunts the lower winding of relay 73 by its upper winding, thereby reducin the resistance in series with rela 67 su iciently to allow it to ener he relay 67, upon energizing, groun s the conductor -118 at ground G2 and disconnects the line 4 107 from the switch E by separating springs 240 and 241. The simultaneous energization of relays 67 and 76 completes a circuit extending from one 'terminal of generator R through springs 242 and 243, springs t244 and 240, thence over the heavy conductors through the resistance 15 and talking circuit at substation A in multiple with the ringer 78 at substation A, then back over the other side of the line, through springs 245 and 246 of relay 67 and sprin 247 and 248 of relay 7 6 to the other terminal of the generator R. As previously cxplaned, the current furnished y generator is not of the proper fre uency to ringebells 78. However, as the ca ling subscri r continues te press the button 15-tl1e magnet 68 continues to rotate the Wheels 71 and 72. After a. short time the engagement an the wheel 72 permits the springs 75 to come into en agement, whereby the circuit of the relay 7 1s closed. The relay 77 operates in conjunction with the relay 67 to connect the generator R with the callingl line. This generator supplies current of the proper frequency to ring the bells at substation A. As long as the call ing subscriber continues to press the button the calling line will continue to be supplied with ringin current from the generators R and R a ternately. As plreviously explained, there is a'short eric of time after either pair of springs 4 or 75 is disengaged before the other air comes into contact. Durin this perio of time both of the relays 76 an 77 are` denergized and the circuit;y of theA u per winding of the relay 73 is broken. he current t rough the relay 67 is reduced suliiciently to allow its armature to fali back. If the button at the calling substation is released at this time or if the called subscriber has removed his receiver, the rela 89 of the Selector E energizes and brea the circuit of the lower winding o f the relay 73, which denergizes and allows the rin 'n interi-opter mechanism to stop. If t e4 utton at the calling substation 1s released while either of the pair of springs 74 or 75 is in contact, the relay 89 remains denergized, because its circuit is open at the springs 240 and 241 of the relay 67,l until both pairs of sprin s 74 and 75 are separated and the relays 6 and 77 are both denergized, whereu on the relay 67 denergizes an connects t e line 107 with the trunk con uctor 117, causin the relay 89 at the selector E to energize an cause the ringing apparatus to come to rest, as previously explained.

When both the subscribers replace their receivers the line relays at the selector E deenergize and allow the line switch C to be released in the manner already explained.

As described, the substations A and A may call each other by simply pressing a button. These substations, however, are called from other lines through selector and connector switches in the regular manner.

As before mentioned, the rin ers at the substations A and A' are adapte to current furnished by the generators R and R', respectively.

It is to be understood that the connectors which are used in calling either of the substations A or A are supplied with the various frequencies of ringing current whereby only one of said substations on the party prings 74 -are forced out ot line is signaled when a call is made to said' line from any other line in the system.

It will be seen from the foregoing that I provide a three-Wire automatic telephone exchange system in which the party-lines are operated on the two-Wire principle, whereby interference between subscribers on the same line is more easily prevented or taken care of, and in which one subscriber calls another on the saine line Without the necessity of first operating the calling mechanism at the substation of the calling subscriber. The ring-back arrangement described and shown is responsive to the push button at the calling substation when one party-line subscriber calls another on the same line, and the successful operation of this push button is only dependent upon first shifting the tele hone instrument at the calling substation-t at is to say, upon first removing the receiver from its hook. Thus a calling suscriber on a party-line may cause ringin current to be projected back over the ca ling line for what is known as a reverting call by simply pressing a push but-A' ton at the callin substation, and without operating the ca ling mechanism at said station.

What I claim.as my invention is 1. In a telephone system, a party line, a push button for each substation on said linez a telephone instrument at each substation, means for extending connection to and from said line, means responsive to said push buttons for signaling the subscribers on said line, dependent only on a preliminar non-numerical switching operation for the ine, and a ogressively movable nonr numerical switch) for performing said opy calling eration.

2. In a telephone system, a party line, means for extending connection to and from said line, a calling mechanism at each substation, and means for projecting a pliirality of ringing currents of different Yfrequencies onto the line, one at a time, whenever one subscriber calls another on the same line, a push button at each substation, whereby the subscribers on said line may control said ringing means to call each other without operatin said mechanism, :said ringing means being common to all of the substations on Said line.

3. In a telephone system, a partyline, a calling mechanism at' each substation, automatic switches r'esponsiye to said mechanism to extend connectibn from said l e, and means including a ringing arrangem nt at the central station byw ich the one subscriber calls another on the saine line without oeratin said mechanism.

4. iii a te ephone system, a party line, a mechanism at each substation on said line, means responsive to said mechanism to extend connection from said line,

and means including a rin ing arrangement at the central" station which any subscriber calls another on t e same line without operating said mechanism.

5. In a telephone system, a partyline, a calling mechanism at each station of the party line, automatic switches responsive to said mechanism to extend connection from said line, and means for enabling the partyline subscribers to call each other without usin said mechanism, the means for extendin connection from said line including a com ined selector and repeater, as set forth.

6. In a telephone system, a party line, a push button for each substation on said line, a telephone instrument at each substation, means for extending connection to and from said line, means responsiye to said push buttons for signaling the subscribers on said line, dependent only on a preliminary nonnumerical switching operation for the line, and means for performing said operation, the means for eixtending connection from said line including a combined selector an repeater, as set forth.

In a telephone system, a party line, means for extending connection to and from said line, a calling mechanism at each silbstation, and means for projecting a plurality of ringing curr ts onto the line, one at a time, whenever o e subscriber calls another on the same libe, including a push button at each substation, whereby the subscribers on said line call each other without operating said mechanism, the means for extending connection from said line including a combined selector and repeater, as setforth.

8. In a telephone system, a party line, a

calling mechanism at each substation, means responsive to said mechanism to extend connection from said line, and means including a ringing arrangement ,at the-central station by which the one subscriber calls another on the same lineV without operating said mechanism, the means for extending connection from said line including a combined selector and repeater, as set orth.

l 9. In a telephone system, a party line, a calling mechanism at each substation oniisaid line, means responsive to said mechanism to extend connection from said linei and means including a ring arrangemnt at the cent-ral station by wliih any subscriber calls another on the same line without` operatin said mechanism, tle means for exten ing connection from sai line including a 'combined selector and r peater, as set forth. 4

10. In a telephone system, a party line, a calling mechanism at each station of the lparty line, automatic switches `responsive to said mechanism to extend connection from said line, and means for enabling the 1:30

party-line subscribers to.A call each other.

without using said mechanism, the` said mean: for cxndin connection from tho lincbeng controllo over the two sides of 5 the line 1n series, nndincluding means for repeating im ulses from the twojwir'e line circuit to a t ree-wire trunk circuit, as set forth.

11. In n telephone system, a. party line .0 a push button for each substation on scid lino, a telephone instrument at ouch substc tion, means for extcndingconnection to und from said line, means responsive to said push buttons for si aling the subscribers on suidline, depen ent only on a preliminary non-numerical switching oporntion for the lino, means for perfornnng said opera.- tion, tho said means for extcndin connection from thc'linc being controied over the twosidesof the line inscries and including ymeans for repeating impuises from the two-wire-1ine circuit to n three-wire tron circuit, ,as set forth.

12. In a telephoncsystem, a party line,

menus for extending connection to and' from said line, n. calling mechanism at euch substation, nnd mcuns for projecting a. plurality oi'l ringing currents 'onto the. line, one nt a time, Whenever one subscriber calls another 3Q on the' same dine, inciuding`-a push button nt cach substation, whereby 'thcvsubscrbers on said 4line call nach 'other without operntini,f said mechanism, thc said means for cxtenclin connection from the lino being controller over the two sides of the line in.

series, and including means for repeating impulsos froml thetwo-wire lino circuit to u three-wire trunk circuit, as set forth.

13. In a telephone system, a party line, a 40 milling mechanism at ouch substation, means responsiiftosnd mechanism to extend connoction from lsnirl'linegand means including a ringing arrangement nt the control station by Lwhich the one subscriber calls il'nothcr 46 on 'thc snmc linc without o rrctings;- said mechanism, the. said ,means or 'extcnding connection from thc lino being.: controlled ovcr the ttvofsirlus of thc/line in serios, und including moans for rcpcuting impulsos `5o from the tw-wirc'lina clrcui'tto a rthroewirc trunk circuit, assct forth.

14. In u. tolcplmnc system, :i party line, u.; calling mcchunism nt noch substation on fsuifl lino. mcnns 'responsive to sailhmcchanisrn to 'cxtolnd connection from said lino'` nml moans :including a' ringing nrrungunu-nt nt tholccntriii Station by which my sub- 'scrihcr coils onother'onthu sumo line withY ont operating,r said nioohunisrn, 'the said 0 Amoans for rxtrndilng connmftion from the lino boing controlled nrt-r thc two sides of thu lino in sofrirs. nml innlnlingfmcans for rcpnniing impulsos from the two-wirr. lino circuit-to n vthree-wire trunk circuit. as set stutiomn plurality of ringing generators 15. In u taiephone' system, n. party line, n. callin mechanism ut euch station on said. party me, cplurnlity of trunk lines, u. switch individual to said line .for sclccting un idle trunk, mechanism in sold trunk for projecting` different. kinds of ringing curront onto said liuc, n push button at cau-h Subscriber@ stution for controlling Suid pro- 'ieoting mechanism over tho two ,sidi-.n of tho ine in' series, nml u control buttery for snpplying the system with curruut for talking purposes.

16. In a telephone system; a party liuc, u. pluralt of stations on .sufl liuc, n, plurality of trun lines, n/swith imlvidlull to sind lino for selecting nu idle trunk, n rulny in Suid trunk, n push button :it the subscribers station for controlling said relay over tho two sides of tho line in scrirs, moons controlled by scid relay for projecting difforent kinds of ringing currcnt onto said lino, and a central buttery for supplying the sy tcm with current for talking purposes.

17. In n telephone system, a party lino. a plurality of stations on said lino.. n lnrnlity of trunk lines, u .su-'itch individua lo said line for selecting an dlo trunk, n relay in suid trunk, n push button ut the sohsorihel"s station for controllingsnid lclny over tho two sides of the. line in series, means controlled by Suid rclny for alternati-.ly projccting n plurality1 ofV different kinds of ringing currents buck onto suid liuc, und n central buttery for supplying thc system with current for talking purposns.

1S. ln u lclophonc systum, n purtylinc, u plurality of stations on scid lino, n switch individual to snid lim` nud conirollod over both sides of snid linc 'in scrios for selecting un idle trunlcextcnding thcrcfrom, n second antomntic switch at the opposite uml of unid trunk, n mlny in snid trunk for controlling 'thc application ofv diffcrcnt kinds of ringing current onto: snif] suhscribcs line, u, sccond relay in Suid lust-.mentioned automatic switch for controlling scid firsbmentioncxl relay, means for mmtrollinnr said second vrelny from thc snhscribcrs station, und n central battery for supplying the system with current or talking; purposes.

I9. l'n n tclophonc system, n party-lino.

n push button for rnc-h .snhstution on snirl lino.. u tolophono -instrnnwnt nt euch substrition, inc-uns for uxtundng.' moulu-,tion to und from said lino, u. source of ringing r'nrrcnt at! thc control oIlh-.n rospnnsru to suid push buttons for signaling the snhsrrihrrs on Huid line, depcndunt only on n preliminary nonnulmricnl switching rim-.ration for thc Iinr. und n progrcssivoly lnnvulilr non-nonwriwil switch-.for Vpr-.r'ormiiig snid operation. 2.-; 1f-

20. ln u tolophonc vsfmmn purify-lion` monos for oxtcndlng cnnucctmn to and trom sunl-l|no, :trailing mechanism nl: cach sub :,aeayess. 1

at the central station for producing ringing current of different frequencies, -and means for projecting different :frequenciescf rin ing current rom said generators onto t e 5 line, one at a time, whenever one subscriber calls another onthe same line, said means including a push button at each substation whereby the subscribers oxr said lino call each other without operating said mecha- IUSIII.

21. In a telephone system, a subscribers station, a line terminating at a central ollice, a signal for said line at said station, means for controlling said si al by current from e source at the central o 'ce by closing the lino and by then var ing the line resistance only once, whereby tli ia] is operated u n c si the Erst variation of tie line resistance a .the closure of the line, the means for varying the resistance being manually operated and individual to the line, and a switch o perated upon the closure of the line to extend l the line into association with the source of signaling current.

station, a line terminating at a central ollice, a signal for said line at said station, a trunk, means for connecting said line and trunk, means for controlling said signal by current from a source at the central oce over said trunk li varying the line resistance 4only once w ereby the si nal is operated lupon the rst variation of t e line resistance after the closure of the line, said means for varying the line resistance comprising manual y operated means individual to said line.

23. In a telephone system, subscribers stations, a line terminating at e central oflice, a pair of signals for said line at said for ccntrollin one o said signals and another kind o? current for controlling the other, equipment for controlling said means to bring. said signals into action by closing. the line and then varying the line resistance.

24. In c telephone system, .subscribers stations, a line terminating in a central of lice, a pair of si als at sald stations, means at the central o ce havin one kind of cnrrent for controlling one o said signals and another kind of current for controlling the other, the equipment for closing the line and for then controlling said means to bring sind signals into action upon the rst variation and for rendering the meansinefiective for such purpose after said first variation.

25. In u. telephone system, a subscribcrs station, a line terminating in a central oiiic'e, a signal for said lino at said station, automatic means for controlling said signal by current from a source at the central oice by closing the line and by then varying the line resistance only once, whereby e si al is operated upon the first variation of t e line station, a line terminati a signal for said line at said station, a trunk 22. In a telephone system, a subscribcrs` stations, means havin 'one kindof current y of the lino resistance after the line closure,

.resistance after the closure of the lineiha i station, a line terminating in the central oflice, a -signal for said line at said station, `meanscomprising a non-numerical progressively movable switch for controllin said signal by closin the line and manually operated means in 'vidual to said line for then varying ythe line resistance only once, whereby the si al is operated by current from the centra oilice upon theirst veriation of the line resistance after the closure of the line.

27. In a telephone system, a vsubscribers in a central dice,-

automatic means for controlling said signa over said trunk b varying the line resistance only once, w ereby the signal is operated from a source -of current et the central oliice upon the first variation of the line resistance after tli'eclcsure of the line, and means .for va ling theline resistance comrisin manu y operated means individual sai line.- 96 28. In a telephone a subecribers station, a line terminating in a central ollice, a signal for seid line at said station, a trunk, means comprising a non-numerical rogressively movable switch for controlling said 100 signal over said trunk by varying the line resistance only once, whereby the signal is operated from a source of current at the central ciiice upon the first variation of the line resistance after the closure of the line.

29.` In a telefibone system, a line, a plurality of signa s on said line, aswitch for said line, a trunk associated with said switch means associated witliseid trunk for controllingl said sgnals,'meaus for operatin 110 said switc in response to e ncn-nuineri impulse from the line for connecting said line and said trunk, said :first means opei'V able upon the first variation of the linenssistance after the closure of the. line, said trunk terminating in a trunk-selectin switch, means for controlling said swim for extenfiin connection from the trunk and for rendring said irst means inoperative. i 30. In a telephone system, a subscribers station, a: line, a signal. for said line at-said lstation, a trunk, automic means for controlling said signal over idA trunk by varya ing the line resistance only once, whereby 126 the signal is operated upon the iii-st variation of the line resistance after the closure cf the-line, means operable for extending connection from said trunk andy for' 'render-1; ing said automatic means inoperative when 130 "lino rosistzinco 4opcralil(` for nxtvndng nonni-.ation from said trunk and for controlling suirl automatic incaus. i

32. lli a iili`|ilionv system. a llni, a signal, a. t'runlli. munis for ronnvoting lulu'. lino and lla' truuk. aulonialliv nn'alin for controlling said si'rnal ovvi' said trunk liy varying tlic -linn i-i'sislaniro only oiuw, wlii'rulii' llico-:igual islopi'l'ntwl upon lli first rai'izilioii nl' llic line i'osislziiwo a ftir lili(I rlonni'u of the. line, an aiitiirnalii tinnkiig: switch oiiiialile for nxtvnfling conniuiiuu 'l'ioin said li'iuilc and for i'vndoi'inig said automatic niuaus inoperative when said lrnnlcing switch is opel-ated` 32h ln a ll'opliono system, a liuc, a. signaal, :i ti'unli, incans for connoitng the lila` and tlio trunk, autoi'inil-'c means for controlling said signal ovvi' said liunk hy varying tliolinol i'c'sistanoo onli,r mice, wlnicliy tho signal is onorati-d upon tflio first vm'ialion ol' tho after the. closuro of tlm liuc, an autoinaticypro ieawiily inovalilv trunk ing Switch opera tion from said trunk and for i'oiulcriiig: said aulo'niairif. moans Viiii'iiinratii-'u .wlivii said ltijiiukinfz! Switch is oporatid.

34; in a -taloplioiic s vsloun a lino` a signal, a trunk. moans comprising a nnn-nnmarical. progriawivoly. movable switch for i-.onixrolling said signal over said trunlc hy varying tlio lino. rosiitancc only once. 4wlinriiliiy' thc. signal-'is inni-amd upon tlm liifst variation of lin. line iiisislainw. allor tlio vlosnro of the lint"` moans oiioitalili foi' cxlondiapj connection 5mm said trunk and I'oi' i'i-ndming said automatic moans Viiioliiii-alive when said rnmms for (intending: ioiincction is operatori. 35. In a lelvplioiio sz'ijatoiii` :i line, circuit a. switch, foi'` said lino. a magia-t, for said switch muniintod with said lino. asicond lino oilmnihjlmiaus comprising said magnet fonopmal-.ing said svi'tchfln conaoot said. firstf'aud siiconil lino circuits, aiitoinalic moana` fordisaonmcting said magnet from said iisi-jliii'c wia-.n tlia-sivil'ifli .is opornticiLV aulomal-ionicans for roliraeiing said switrzli to rostorc'siiid magnet to the said [irsl lino, :i lliird 'vivi-.Init auxiliar)r lo said swioli foi' ifouti'ollinglisaid i1lcaiw-niii1iiis, a ri'lalv in said counvntod lini` (-.iriiiilas foi' oiil'rolling said 'i'iilnasaioii'nuita au i-norgizing circuit foi' aai'il 'relay -i-.xtendiug via aaidl oonntch-.gl cir- -oiiit'iand-foif substitut-ing a nowV mici'gizing )la for extanding ooiinoc-r 'imiionsivv lo llnopi'riilion of' said ringing v3T; ln .a ivlvplioiw ai'stiin. a substation and :i lini llufi-afoi. a trunk lnvterminating iii an aiiioniat'iu swilvli, said swilcli ii-o'- rillvil with inoi'alila ti-xiiiinals foi' extanrling ninna-lion to ollioi' lines. nwalis for morini; said ti-i'iiiiinil.' moans foi' roninctinif, said fil-bl liiii' :ind said truiil: liuc` ringing appai'alua` and a soni'cu ol' ringing nnirrnt ass-ii viali-ii with #aid liiink liiwund iiziiiiis: nl. llii' said Hillalnlinii foi' niuial'ing Hiiiil ringing apparatus to project current from said soin-w oiii llii' said. iii't lini l'ul'ori said niovalili li'i'ninai :ii'i' mm ad.

l. ln a li'liplioua ajliiiu` :i sulisiafiiin and a line` llni-f-foi'. a lruiilc lino lai-niiiifiliug iii nu autom-.itil` Swiich. said Swil'r'h pro` ridad willi nioialilo lmni'iiial for ixiiiidinfz connection to ollwr liins. moans for niiwiiiff said lii'iiiil'ials. 10ans -fni ri'nnn'i'liug will lii'sl lino and said li'nnlc lino. a ringing ifi-ni'ruloi und :i Soui'iziof ringing*i vorrai# asmrialiid willi Said ifi-unl: lino, :ni-an` al llw substation for operating said snilpi: lioforii olivi-ating! said ringing.' apliaizilunand iov-iin: ronirollvil hy tlii initial oa'mlion of 'smid swilrh for riinilm'ing: sairl ringing apparaias iiiopil'alivc. Y

ifl. Tu a igoliiiilimii' syslmn. a willing and a r'allvd suhsfaiion on (liv `anni` liu. a trunk liua lui'niinaling in :in auloniaiiiiitvli uroi'idi-d willi inovalili' {oi-ininals for i'oiinocling with other lions, moans. for moving said 'lirminals. moan.`1 i'osiioiis'ii'v lo liuii'inni'al of llio roi-virtu' al. llnwilling` substation for ofrinniiling said* lirst lino lino. ringing miuiiim-Lnl and a Soni-0c of ringing i-iiri'inl. assoiialwl willi Raid trunk lino.` and moans lfor vonliolliogr said ringing oquiinnviil from lln' "ailing aalistaiion to signal ilu` rfiillvd oulishition'lwfoi'aouirating lliv moi-alditii'minala of said switch.

40. Tn a liliplione avr-lain. n substation and u lino lliorafor. a l'i'iinklino at the cx vliangv aiul inoiiusi For miinicliiig tln. said iii-sl lino llim'iio. :in antonialiisivilcli und a ringing iniiiniiut annui-iam] willi laid lruiik lini,thv forium' for iixivuding ironnw-.ti'on lo other lines and tlio latlor yfoi' projecting ringing curi-nut oi'ci said lirst lllll and said trunk v A 1n thc line circuit of a minnen line, and moons: ut the substation foi* operaia ing either the switch or the ringing' e uinmcnt independently ut thc option o tbe callin"I subscriber.

ilfiin c telephone system, u substation und c line therefor, o trunk line accessible to Suid line und terminating in un nutmun'tic switch, firming equipment associated with scid trunk inc adopted to connect c source of rin ingcurnt with said line, means at sui substation for producing chnnges articular character for operating smid switc and means at tho subst-ation for producn changea in the line,

circuit of e dicrent c nrcctczfor operatinscid ringin equipment.

' In u te op. cnc system a trunk line at the exchange pros'idcd with un cutomutic swimh and u ringing 1elay,c. substation und a circuit therethrough mcludng c. line extendin to the exchange, means responsive to u. nriminary nou-numerical operation at scia substation for connecting scid line and 'trunk line, mexo'lient tbosftid achat-ation for producing diicrcnt changea in the scid cubstntion lino circu.,'ln`euns responsive to one kinal change for operating scid switch to extend the lino 'i1 anot-lierl ix\e, end :nouns responsive to another kind of chungo for operating scifi ringing clay before scid Switch npc-mixed.

43. En a telephone aiya-bem," c. trunk linc terminating in on unicm'oticswitch for con nccting with other lnea, a, ringing relay cesociated with scid trunk line and adopts-,fl to connect the come with c source 4of rin ing current, a. calling substation und. a. yine therefor with moans for connecting 'scid lino with scid trunk line, a. Sccon Buba-'tation on scid line witlithc calling substation, und mcans'including sopor-ctc cicvcce at the calliring substation whcreby the l cnlling 'subscriber t-l'xercot is given the cptionjc ctlicl operating thc said switch to 'connat with :mother to signin! the seid second substation; 'l

4.4. In u telephone-system .n nu ontion 'and a line therefor, a. tml-ik profidctlwitlg' on individual automatic switch nud' cn ,in-f dividoc-l Linging relcy'ymccns 'orccnueclng i Y '-lilineuscsnv net for scid `i-zvfic'n, separato circuits i? 1" said @pointing magnet and for scid ringing scid line :um troni; line, im operating mag? and means controlled by :mid switch for lino or operating said rigin "relay into 'notion eich time thc resistance o mis; ce ich said switch, menne for' operating sind riug` ing relay before scid switch is operated und means whereby scid ringing rela is ren- (lg3d inoperative after sold switch as opera i (i6. In n telephone system, a party line, a. trunk line,v means for extending connection from said stty line to said trunk line, a progressive? movable switch for extending connection rom the trunk, means compris ing a. ringing mln for ringing a subscriber on said party line ack over scid trunk line,

rendering scid second means inoperative. A 47. n a. telephone system, a line, u signal on said line, a tmuik line, another lino, an automatic proreivoly movable switch for connecting sai lincnnd trunk lino, an untonmtic progressively morcilla switch for con` nec-ting said trunlr. with said other line, c source of current associated with scid trunk, menus conti-oiled over scid trunk for cousingscid signal to be operated `'from said source over said line be'ore scidV secondswitch is operated menno for operating said second switch, nml xncein'oontrolled by such operation `for preventing so' conttollingl ccidY signin.

lil-Inn to e hone system, substations, a line terminating in a central olice, 'a pair of si als nt scid stations means at the central c ico having one hind ofl current for controlling onc 'of Suid Signals and :mother kind of current for controlling the other, equipment for closing the line and for thon contolling scifi. mccnsto bring said' ai als the linefis `curiosi uiten the lino is closed. 10h S1 4 ed byme ct nico 0,' Cool: county, dew-,affine 1910. A. Y

, mfrzgnuiinnuonn.

scid rnefins from Ecmnc'D. Alumina J. Rn. 

